Finite Element Analysis of the Dynamic Behaviour of Concrete and a Glass Fibre Reinforced Composite Sleeper for Traditional and High-Speed Rails

This paper presents a comparative finite element investigation of three sleeper models: a prestressed monoblock concrete sleeper named Model 1, a GFRP sleeper with identical geometry but no reinforcement named Model 2, and Model 3 for a GFRP sleeper with a composite sleeper standard geometry according to ISO13230-1. Harmonic response analyses under 180 kN and 320 kN axial loads revealed severe dynamic deficiencies in Model 1, with extreme resonance-induced stresses reaching 5629.1 MPa at 714 Hz under 320 kN, which exceeded the concrete strength capacity. Although Model 2 benefited from GFRP’s enhanced damping, its standard geometry led to critical stresses up to 839.0 MPa at 324 Hz, which is beyond the GFRP yield strength (75 MPa). In contrast, Model 3 demonstrated effective stress control under 180 kN, meeting IRS safety requirements with peak stresses of 74.2 MPa at 250 Hz. All models exhibited a peak response at their third vertical bending mode, however, GFRP sleepers showed smaller amplitudes which confirms their stability under dynamic loads. Dynamic advantages of GFRP sleepers are fully realised through concurrent optimisation of material properties and geometry. These outcomes show the potential of GFRP sleepers as a robust, safer, and more durable alternative for next-generation high-speed railway infrastructure.